The present invention relates generally to the field of beverage makers, coffee makers, water heaters, and water boilers, and more particularly relates to a flow detection logic for a beverage maker.
Certain water boilers, water heaters, coffee makers or the like, hereafter referred as “units,” use a manual faucet or tap to dispense hot water. In these units, the control circuitry that controls heating of the water does not initiate heating of the water as soon as water is being dispensed. These units' control circuits solely rely on detection of the temperature of the water in the tank to turn the heaters on and off. In these units, the heaters are turned on only when the detected water temperature inside the tank falls below a pre-set limit. As a result, the control circuitry can not anticipate the need for heating the water. The drawback of this approach is that it creates a delay between the time when water is being withdrawn, and when the heaters are turned on.
In an attempt to overcome the problem of delay between dispensing of hot water and heating of water, current units are often equipped with a device called an “anticipator tube” as is illustrated in FIG. 1, showing a prior art water heating system 10 for a beverage maker unit, which typically includes a water tank 12 enclosing an interior chamber 14, and a cold water inlet conduit 16 connected to the water tank, with the anticipator tube 18 connected to the cold water inlet conduit. A hot water outlet conduit 20 is connected to the water tank and includes a manual hot water faucet outlet valve 22 with a faucet lever 24 for operating the manual hot water faucet outlet valve. The faucet lever is typically movable between a faucet outlet valve open position and a faucet outlet valve closed position. A temperature measuring device 26 is also provided in the tank adjacent to an outlet end of the anticipator tube, so that as cold water is supplied to the water tank, the anticipator tube introduces cold water into the water tank near the temperature measuring device, lowering the water temperature in the vicinity of the temperature measuring device. One or more heaters 28 are connected to a heater control logic unit 30 which receives a temperature signal from the temperature measuring device, so that when cold water is flowing into the unit to replace water being dispensed from the unit, cold water is directed onto the temperature measuring device to artificially lower its temperature, hence turning the heaters on earlier. The drawbacks of this concept are the following:
First, for this system to be effective, cold water is to be sprayed near the temperature measuring device, which is often located at the top of the water tank, close to the hot water outlet. As a result, the cold water introduced at the top of the water tank by the anticipator tube reduces the water outlet temperature, which is not a desired effect.
Second, as the cold water from the anticipator tube mixes with the hot water around the temperature measuring device, the temperature around the temperature measuring device drops fairly slowly. As a result, it often takes 15 to 40 seconds of cold water flow from the anticipator tube for the unit's control circuit to turn the heaters on. This delay causes the overall temperature in the tank to drop more rapidly, and also increases the overall re-heating time.
Third, the orientation and location of the anticipator tube has to be adjusted so the right amount of cold water is sprayed on the temperature measuring device. Not enough cold water sprayed onto the temperature measuring device would render the water heating system ineffective, and too cold water sprayed onto the temperature measuring device much would eliminate completely the temperature sensing capabilities of the unit control circuitry, potentially causing over-heating of water in the tank. This adjustment is not only required at the factory, but is also required throughout the life of the product, hence increasing the manufacturing, maintenance and repair costs.
It would therefore be desirable to eliminate these performance drawbacks. The present invention addresses and solves these and other problems associated with heating of water in a beverage maker.